Manufacture of reduction products of sulfurous acids and salts thereof.



ICE SEECKEEJEE Al '3, QJlT-El-IE-MAIN, GERMfiIT I, A

TD EIGUAED MARBURG, G13 GRIESHEZL'lVlI-ON-THE-MAIN, GEE- NY, iiSfiIGNQES T0 GHQ-a ""SCHE FABRIK GR-IESI-IEIM-ELEKT'RON, GT3 FRANKFOBT- CORPORATION OF GERMANY.

IvIANUFAC'EUE-E GE REDUCTION PRODUCTS OF SULFURGUS ACIDS AND SALTS THEREOF.

lie Brewing.

1'10 all whom it may concern:

it known that we, Hammett Senoritaand licence Milanese, both subjects of the GermanEmperor, and resident of Griesheila-onthehlain, Germany, have invented certain new and useful improvements in Connection with the Manufacture of Roi duction roducts of Sulfurous Acid and ployed and the use of spongy zinc in addi-- tion to thus enabling the operation to becarried on much more expeditiously than hitherto )resents the further advanta e' that even with the more rapid supply of sulfurous acid, excessive'acidity and decomposition of the solution of hydrosulfite do not occur.

As spongy zinc can be very easil obtained from zincoxid, zinc hydroxid', zinc carbonate, or waste containing oxidizable zinc, and as the oxidized waste resulting from the reduction process can be readily regenerated, spongy zinc is not only much cheaper than zinc dust but has also the advantage that in consequence of its easy recuperation the process can be conducted with a minimum of zinc and the industrial carrying out of the reduction process is'not only simplified and expedited by the end-- ployment of spongy zinc but it is also considerably cheapened, and this is of great importance in the manufacture of reduction products of sulfurous acid, because the price of zinc dust has formed a large item of the total cost of production, even taking into account value of the resulting residues containing ZlIlC oxid. I

The fact that, although spongy zinc obtained by electrolysis has been long known it has notv been used in place of zinc dust for the production reduction products of end 5 Specification of Letters Patent.

Application filed February 2, 1914. SerialNo. 816,063.

furous acid, and salts thereof may be accounted for by the fact that no industrial advantage was foreseen, and it'was supposed that spongy zinc would not be sufficiently durable.

In the production of aldehyde sulfoxylate spongy zinc possesses another important, and hithertounknown property for the purpose of the reduction. We have found that, by starting from a ready-made alkali-bis ullite-formaldehyde, or from a formaldehyde sulfite mixture :such as hydrosulfitformah dehyde, i. c. a mixture or double salt of bisulfite-formaldehyde and formaldehyde-Sid roxylate, it is possible to readily obtain, without any further addition, an excellent yield of formaldehyde sulfoxylates, if spongy Zinc obtained by electrolysis be used as reducing agent The yield is in this case about 85 ,to 90 per cent. Hitherto it has not been possible to carry out successfully the direct production of the formaldehyde-sulfoxylates by reduction of the ready made alkali-bisulfite formaldehydes or hydrosulfite-formaldehydes by means of zinc dust without the use of considerable quantities of an addition for insuring the favorable run of the reaction; For instance in accordance f with the specification 'ofGerman Patent No. 165,807 an addition of acid (for instance acetic acid) is needed. In accordance with the specification of German Patent No. 222,195, the desired efiect is obtained by the addition'of Zinc-, or ammonium-sulfite,-or -bisulfite, or by the addition of the zinc-, or ammonium'salts of formaldehyde-sulfurous acid, or of formaldehyde-hydrosulfurous zinc hydroxid, or zinc carbonate, more than;

60 per cent. of the full equivalent of zinc paid being added. The same object, namely FT rim he avoidance of an addition of acidand the consequent production of the zinc and alkali salts of this acid, is attained in the process in accordance with thespecification of German Patent No. 20224-2. in which it is proposed to cause sodium bisullite, formaldehyde and zinc dust to react on one another at a full boiling heat. In this case too the addition which is essential for the reaction is the suitably chosen excess or free sodium bisulfite, starting from the ready formed bisulfite formaldehyde 9 being expressely avoided.

As zinc-dust itself is a i'ery energetic and finely dividing reducing agent, it was not to be foreseen that by using electrolytically prepared spongy zinc, it would be possible to give up the use of the additions hitherto employed.

The following are examples of how this invention can be carried into effect, but we do not limit ourselves to these examples.

Example 1: Sulfurous acid is passed into a quantity of moist electrolytically prepared spongy Zinc containing 100 kilograms of metallic zinc under 300 liters of water, while being well stirred and cooled, until the zinc has for the greater part disappeared. The zinc hydrosulfite solution obtained is decomposed by means of a suitable alkali salt, for instance sodium carbonate, tered. i highly concentrated solution of sodium hydrosulfite is thus obtained.

Example 2: 152 kilograms ot'sodium bisulfite-formaldehye (NaHSO CILOII O) dissolved in from 200, to 250, kilograms of water are stirred with a quantity of moist electrolytically prepared spongy zinc containing 100 kilograms of metallic. zinc and well boiled for from 1 to 2 hours while being stirred. The solution filtered off from zinc sludge contains from 130 to H0 kilograms of sodium formaldehyde-sultoxylate. By

evaporating at low temperature preferably in venue, the solid salt is obtained.

. Example 3: A solution of 305 kilograms of sodium hydrosulfite formaldehyde in 850 liters of water is stirred with a quantity of moist spongy zinc, electrolytically prepared and containing 100 kilograms of zinc and boiled for from 1, to 2, hours while stirring.

- messes alkali-hydrosulfite-formaldehyde by spongy zinc to form alkali formaldehydesulfoxylate.

3: The process'of producing hydrosulfurous acid compounds from sulfurous acid compounds which com-prises reducing such sulfurous acid compounds by ,means of spongy Zinc. i 4. The process of producing alkali formaldehyde-sulfoxylate which comprises reducing an alkali-formaldehyde-bisulfite by means of spongy zinc electrolytically'pre pared.

5. The process of producing alkali formaldehyde-sillfoxylate which comprises reducing an alkali-formaldehyde hydrosulfite by means of spongy zinc electrolytically prepared. v

6. The process of producing sodium-formaldehyde sulfoxyl'ate which comprises re ducing sodium-formaldehyde-bisulfite by means of spongy zinc electrolytically prepared. I

7. The process of producing sodium-formaldehyde-sulfoxylate ducing sodium hydrosulfite-iormaldehyde by means of spongy zinc electrolytically pre pared.

In testimony whereof we have signed our names to this specification in the presence of two subscribing witnesses.

l-lEINRICH SPECKETER: EDUARD MARBUBG. Witnesses:

JEAN GRUND, ELSE Menus.

which comprises re-. 

